<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<title>创建BFC的区域不计算绝对定位的元素的高度</title>
	<style>
		.container{
			height: 400px;
			float: left;
			background: darkred;
		}

		.item{
			background: lightblue;
			width: 100px;
			height: 100px;
			position: absolute;
		}
	</style>
</head>
<body>
	  <div class="container">
	  	<div class="item"></div>
	  </div>
</body>
</html>